I. Field of the Invention
The present invention relates to object-sensing systems, and more particularly, an on-site system that transmits ultrasonic signals and then detects reflected signals to determine whether cargo is present in a freight trailer. This system may also send a representative report to a remote location.
II. Description of the Related Art
A number of carriers and logistics-based businesses are utilizing the OmniTRACS(copyright) system, which is a mobile information management system provided by QUALCOMM, Inc. The OmniTRACS system is an interactive information management system that includes two-way mobile communications, satellite tracking, and fleet management software. OmniTRACS system includes integrated mobile hardware, network management services, and application software. The OmniTRACS system manages data flow in areas related to communications and tracking, maintenance and performance monitoring, mileage reporting, driver e-mail, and the like.
One further development of the OmniTRACS system has been the TrailerTRACS(copyright) product. The TrailerTRACS product monitors various raw statistics concerning the state of freight vehicles, such as semi-tractor trailers. For instance, the TraiterTRACS product can monitor trailer identification, geographical location, load status, refrigerator operation, fuel usage, engine properties, brake behavior, transmission activity, safety-related statistics, and other parameters. The TrailerTRACS product also provides various analytical information, such as notifications or alarms that occur when a trailer is lost, there are too many or too few trailers at one location, there is an unauthorized trailer drop, the wrong trailer is connected to a truck, an unscheduled movement occurs, etc.
Although products such as OmniTRACS and TrailerTRACS have introduced significant benefits to their customers, the present inventors seek to expand and improve capabilities of products such as these. In this respect, one area of recent focus has en sensing the presence or absence of cargo in a semi-trailer or similar freight car.
Although some recent attempts have been made utilizing ultrasonic transmitters and receivers to sense cargo, they have encountered some technical challenges. Sensing accuracy is influenced by various factors, such as humidity, temperature, beam orientation, and the like. Also, false cargo sensing can result from the nearby presence of small objects (which can appear as large objects or even a full load), the presence of ceiling ribs or other structural members of the freight car, etc.
Sensing anomalies and other errors like these can result in inaccurate output signals, defeating the entire purpose of performing cargo sensing in the first place.
Consequently, existing ultrasonic cargo sensing systems are not completely adequate for some applications due to certain unsolved problems.
Broadly, the present invention concerns a system for sensing and reporting the presence or absence of cargo in a semi-trailer or similar freight car. The freight car has a proximal (xe2x80x9crearxe2x80x9d) end with a loading door and also has an opposing, distal (xe2x80x9cfrontxe2x80x9d) end. Initially, one or more transmitters and receivers are mounted inside the freight car at the front end. Because cargo is typically loaded against the front wall, the transmitters/receivers are mounted toward the ceiling to minimize the possibility of damage caused by loading and unloading cargo. The transmitters/receivers are operated by a controller, which also functions to analyze data from the receivers and transmit related reports to a remote monitoring site. In one embodiment, the transceiver is operated to detect objects in the front third of the freight car, and if any such objects are detected, the controller reports the freight car as being xe2x80x9cfullxe2x80x9d.
More particularly, the controller operates the transmitters/receivers as follows. During a prescribed time period, the controller directs the transmitter to generate a sonic signal pattern. As an example, the signal pattern may effectively reach and reflect from objects in the first third (approximately) of the car""s length. The signal pattern may be intentionally shaped to avoid detecting low-lying boxes, pallets, blankets, dollies, ladders, and the like near the front of the car. During the time period of transmission, or slightly later to account for signal reflection time, the controller operates the receiver to detect reflected signals originating from the transmitter.
After this period, the controller transmits a report of whether any cargo is present in the freight car. This is achieved by transmitting a representative output signal, which indicates xe2x80x9cfull loadxe2x80x9d if any reflected signals are detected during the time period. Otherwise, if no reflected signals are detected during the time period, the controller reports that the freight car is empty.
The foregoing features may be implemented in a number of different forms. For example, the invention may be implemented to provide a method to determine whether cargo is present in a freight car, as shown by various techniques explained herein. In another embodiment, the invention may be implemented to provide an apparatus such as an on-site cargo sensing and reporting device. In still another embodiment, the invention may be implemented to provide a signal-bearing medium tangibly embodying a program of machinereadable instructions executable by a digital data processing apparatus to determine whether cargo is present in a freight car. Another embodiment concerns logic circuitry having multiple interconnected electrically conductive elements configured to determine the presence of cargo freight as shown herein.
The invention affords its users with a number of advantages. Beneficially, the invention utilizes carefully patterned sonic beams to probe for cargo in a freight car, analyze the received signal reflections (if any), and transmit a representative report to a remote site such as a monitoring base station. Fleet managers benefit from having such information, because they can remotely monitor cargo status of their freight cars. The transmitted beam pattern gives the invention a particular advantage by reducing unwanted signal feedback from structure of the freight car itself, and from ever-present low-lying objects in the car""s front end. The invention also provides a number of other advantages and benefits, which should be apparent from the following description of the invention.